Background: Several reports have raised the possibility that newly addressed lipid measures might be superior to the traditional ones for cardiovascular risk prediction. However, data on the associations between these lipid measures with metabolic syndrome (MetS) is limited. Methods and Results: A cross-sectional study of participants in routine health examinations was performed. The associations between lipid measure variables (total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), TC/HDL-C, LDL-C/HDL-C, TG/HDL-C ratio and non-HDL-C) and MetS, insulin resistance (IR) by homeostatic model assessment (HOMA) and adiponectin were analyzed in 6,546 participants (3,820 men; mean age 46.0±9.2 years in men, 44.6±9.5 years in women). In multivariable adjusted regression analysis, the 3 lipid ratios of TC/HDL-C, LDL-C/HDL-C and TG/HDL-C showed significant association with the number of MetS components, HOMA and log adiponectin level in both men and women without MetS (P<0.001, respectively), though these relations were weaker in participants with MetS. The mean levels of the lipid ratios also associated with increasing numbers of the MetS components, quartiles of HOMA and adiponectin. Conclusions: Lipid ratios of TC/HDL-C, LDL-C/HDL-C and TG/HDL-C, as well as TG and HDL, were consistently associated with MetS and IR in participants without MetS. Lipid ratios might be used as integrated and simple lipid measures. (Circ J 2010; 74: 931 - 937)